by William M. Welch, USA TODAY

by William M. Welch, USA TODAY

Authorities searched on foot and in armored vehicles through heavy snow in the mountains east of Los Angeles without finding any further sign of the former cop who went on a self-confessed revenge killing spree.

Los Angeles police maintained heavy patrols and watches in the city, too, Friday as they waited for Christopher Dorner, the ex-LAPD cop who is the subject of a massive manhunt, to surface.

"We hope it ends quickly without any more bloodshed or anyone else getting hurt,'' Los Angeles police Cmdr. Andrew Smith said. "We are prepared to go as long as it takes. We're in it for the long haul.''

Officers from other agencies were focused on the Big Bear mountain ski area for Dorner after police found his burned-out pickup and tracks leading away from the vehicle off a forestry road in a remote area of the San Bernardino mountains.

"We're going to continue searching until we discover either that he left the mountain or we find him,'' San Bernardino Sheriff John McMahon said.

Police said Dorner, wanted in connection with three deaths, began his wave of violence as retribution after being fired in 2008 for making false statements, following a hearing by a police review board. Smith said the decision of the board, which included a civilian, was backed up by the chief of police and in court appeals.

"He went to court on several occasions afterward to try to get his job back'' without success, Smith said.

The police headquarters building in downtown Los Angeles was ringed by officers on foot and parked patrol cars, and snipers were in place on the roof in case the wanted ex-cop who vowed warfare against police and their families made a move there. Other police stations throughout the area had heavy visible protection as well.

"Here's the bottom line: We don't know if he's on foot or not," Los Angeles Deputy Chief Kirk Albanese told the Associated Press. "Is he on foot up on the mountain? Is he down the mountain? We don't know."

McMahon said police followed tracks in the snow around the truck until they lost the trail. He said they also went door to door and checked vacant vacation homes in the area and would continue through the day.

Snow was falling and temperatures were not expected to break out of the 20s before nightfall. McMahon said police had no information on whether Dorner may have cold-weather gear, camping supplies or any equipment to help him cope with the snowstorm.

Schools were closed in the resort area. Skiing resumed at the two big ski areas, Bear Mountain and Snow Summit, after being halted a day earlier because of the manhunt.

Police were unable to search by air because of the weather, McMahon said, but they searched on foot and used snow equipment, dogs and armored personnel carriers equipped with chains to move searchers into position in elevations of 7,000 feet or higher.

McMahon said investigators finished going through the burned out remains of Dorner's truck, which was discovered and towed from the mountain, but he declined to provide any information on what police may have found inside the vehicle.

The truck was turned over to Irvine police for investigation in their double murder case. Irvine Police Lt. Julia Engen said the department would not comment on its search for evidence in the truck.

Police chiefs in Irvine and Los Angeles said Dorner wrote and posted online a profanity-laced 11-page note addressed to "America." In it, he laid out his grievances against the LAPD and various officers he claims wronged him, ruined his law enforcement career and ultimately destroyed his reputation. He says he'll stop the killing when the LAPD publicly proclaims his innocence and restores his reputation.

"I will utilize every bit of small arms training, demolition, ordnance and survival training I've been given," the manifesto read. "You have misjudged a sleeping giant."

McMahon said 125 officers were going door to door and attempting to track the suspect, and that a SWAT team was providing added security to those in the community.

As a precaution, deputies were posted around Norwalk Christian School in Norwalk, Calif., where Dorner says in his manifesto that he first encountered racism on the playground in the first grade. The elementary school was also closed for the day, KTLA reported.

"That day I made a life decision that I will not tolerate racial derogatory terms spoken to me," he writes about the incident at the elementary school.

Law enforcement officials are looking for more clues in a package CNN's Anderson Cooper received from Dorner. CNN spokeswoman Shimrit Sheetrit told the Associated Press on Thursday the parcel contained a note, a DVD and a bullet hole-riddled memento. The note read, in part, "I never lied."

The package arrived Feb. 1, days before the first two killings Dorner is accused of.

"I don't think there's anybody in law enforcement who isn't looking for him, along with about half the commuters in Southern California,'' said San Diego police Detective Gary Hassen.

Beck said Dorner was threatening law enforcement officers specifically and in general.

"LAPD is a specific target, but all law enforcement is targeted,'' Beck said, because Dorner had "a vendetta against all Southern California law enforcement.''

Police in San Diego early Thursday recovered a badge and ID bearing Dorner's photograph, Hassen said. The items were found by someone near the San Diego airport, he said.

Hassen said a man matching Dorner's description tried to steal a boat from a San Diego marina Wednesday night but gave up after he was unable to get the engine started and the boat unmoored. "We're waiting for forensic evidence to see if it was Dorner,'' Hassen said.

Police across the region were responding to reported sightings, and some proved to be mistaken. Beck attributed a pair of shootings by police officers in Torrance, south of Los Angeles, to mistaken identity. In one of the instances, officers fired on two women who were in a blue pickup delivering newspapers. One was hospitalized, the other treated for minor injuries.

Riverside Police Chief Sergio Diaz said his two officers were stopped at a traffic light when they were hit with several gunshots fired from a rifle by someone in a truck that pulled up next to them. A 34-year-old officer with 11 years on the force was killed. Another officer, 27, is expected to recover from his injuries, Diaz said.

Irvine Police Chief David Maggard named Dorner Wednesday night as the suspect in the slayings of Monica Quan, 28, an assistant basketball coach at California State University-Fullerton, and her fiance, Keith Lawrence, a University of Southern California campus security officer.

The couple were found dead of multiple gunshot wounds in their car outside their Irvine condominium Sunday night.

Quan was the daughter of Randy Quan, a retired LAPD captain who represented Dorner in the review process that led to his dismissal from the force for making false statements.

Randy Quan was the first Chinese-American to attain the rank of captain on the LAPD force, the department has said. He later served as chief of police at Cal Poly-Pomona, part of the California State University system.

Maggard said Dorner implicated himself in the killings in the manifesto.

"When the truth comes out, the killing stops," the letter reads. "The attacks will stop when the department states the truth about my innocence. PUBLICLY!!! I will not accept any type of currency/goods in exchange for the attacks to stop, no do I want it. I want my name back, period. There is no negotiation."

The letter accuses the LAPD of corruption, racism and covering up for and promoting officers who steal and use excessive force. He identifies groups, including white, Asian, lesbian, black and Hispanic officers, who have acted in what he calls immoral ways as "high-value targets." The letter cites as one example of "high-value targets" black officers who belittle white officers under their command, perpetuating the cycle of racism" in the LAPD.

"I am here to change and make policy," the letter reads. "The culture of LAPD versus the community and honest/good officers needs to and will change. I am here to correct and calibrate your morale compasses to true north."